Slip history of the 1995 Kobe, Japan, earthquake determined from strong motion, teleseismic, and geodetic data

Near-source ground motions, teleseismic body waveforms, and geodetic displacements produced by the 1995 Kobe, Japan, earthquake have been used to determine the spatial and temporal dislocation pattern on the faulting surfaces. A linear, least-squares approach was used to invert the data sets both independently and in unison in order to investigate the resolving power of each data set and to determine a model most consistent with all the available data. A two-fault model was used, with a single rupture plane representing faulting beneath Kobe and a second plane representing slip underneath Awaji Island. The total seismic moment is estimated to be 2.4×10¹⁹Nm (M_W 6.9), with rupture partitioned such that about 40% of the slip was relatively deep (5-20 km) and northeast of the epicenter toward Kobe, and about 60% was toward the southwest and shallower (mostly 0-10 km) beneath Awaji Island. Analysis of the slip model indicates that the ground motions recorded within the severely damaged region of Kobe originated from the region of relatively low slip (about 1 m) deep beneath Kobe and not from the shallow, higher slip regions (about 3 m) beneath Awaji Island. Although the slip was relatively low beneath Kobe, the combined effects of source rupture directivity, a short slip duration, and site amplification conspired to generate very damaging ground motions within the city.